It is the long-term goal of this research proposal to determine how the rate of DNA replication is coordinated to the cell division cycle in the model organism of E. coli. Understanding these events in bacteria is essential to guide future cell-cycle research in humans. To achieve this goal, this research project is designed to resolve two questions about replication control in e. COLI: First, what is the role of SeqA protein in regulating initiation of DNA replication, and specifically, what is its role in controlling origin movement within the cell? Second, what is the relationship between the sequence of events occurring at replication termiantion in part controlled by SeqA, and the timing of replication initiation? These questions will be addressed by examining the timing of varius events, by fluorescence microscopy and molecular methods, that occur at and immediately and mutant cells that are defective in the control of replication initiation. In the process of this investigation, we will develop a new method to obtain synchronized cultures.